Tuesday, December 4, 2012

Deleting Data using ADO.Net Entity Framework

In order to select data from a Model
using the ADO.Net Entity Data Model, we should first create an ADO.Net Entity
Data Model class, refer to the post Creating your First ADO.Net Entity Data Model
to see on how to create an ADO.Net Entity Data Model, that maps to the physical
database.

Once you have created the ADO.Net Entity Data Model class, we can
proceed with querying the model to select data. In this post we shall see on
how to use the ADO.Net Entity Data Model to DELETE a record in the
Employee table.

1. Create an Object of the ADO.Net
Entity Data Model class
2. Get the Object of the Employee whose details needs to be Deleted
3. Delete the Object
4. Commit changes to the Model

Here is the code to DELETE rows using the ADO.Net Entity Data Model

EmployeesEntities dbContext = newEmployeesEntities();

//

// Get The
Object of the Selected Employee

Employee
objEmployee = (from emp in dbContext.Employee

where emp.ID == 235

select emp).First();

//

// Delete the
Employee Object and Save the Detils.

dbContext.DeleteObject(objEmployee);

dbContext.SaveChanges();

5.
Once we execute the code, a record for the Employee with ID 235 will get deleted
from the Employee Table.

5.
Notice that we are referring to the Departments object to get the DepartmentID
value for the Employee table.6.
Once we execute the code, a new record for the Employee Tom will get updated in
the Employee Table.